Status report of MPPC mass measurement

15/20

2007/Feb/21

Shinshu Univ.

HE lab. M2

Takashi 　 Tsubokawa1/15

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•Gain measurement•Noise rate measurement

FPCB

　　　　　　　 Gain

　　　　　 Noise rate

ADC

Thermo-static chamber (kept at 15 oC)

Clock Generator Gate generator

16chASD

Discri Scaler

Output register

9chMPPC with FPCB and

1chMPPC 　

Bias voltage

LED

LED Driver

470nm

MPPC

Coincidence

2ndstage-measurement setup(2nd-stage MPPCs with FPCB)

Control PC

One channel on the board is kept as reference

FPCB

・・・

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19/20

Measurement time (data taking)

Gain measurement Change MPPCs ,,,,,,,,,,,,,,,,,,,,,,,,2min(5min) Stabilize temperature ,,,,,,,,,,,,,,,,,,,,,,,,5min(5min) ADC data taking ,,,,,,,,,,,,,,,,,,,,,,,,3min(3min)

Sum:10min / 9MPPC(1 FPCB sheet) Sum:13min / 14MPPC

Noise rate measurement Change MPPCs ,,,,,,,,,,,,,,,,,,,,,,,,2min(5min) Stabilize temperature ,,,,,,,,,,,,,,,,,,,,,,,,5min(5min) Discriminator curve data

taking ,,,,,,,,,,,,,,,,,,,,9min(17min) Sum:16min / 9MPPC(1 FPCB sheet)

Sum:27min / 14MPPC All:26min / 9MPPC(1　FPCB　sheet) (All:40min / 14MPPC)

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Black:2nd-stageRed:1st-stage

Progress 1ststage-measurement have been

finished 600 MPPCs have been delivered

on Feb-8 2007 351 MPPCs with FPCB 249 bare chip MPPCs (without FPCB)

351 MPPCs with FPCB (39 FPCBs) have been measured.

Analysis of 351 MPPCs measurement has been finished.

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Deference 1st-stage MPPCs and 2nd-stage MPPCs (HPK data)

Delivered 1st---------end of Dec(400MPPCs) 2nd--------start of Feb(600MPPCs,351 MPPCs with FPCB,259 MPPC

s without FPCB) Mean operation voltage (Gain =2.75x105 )

1st---------76.43V 2nd--------76.03V

Typical Noise rate at operation voltage 1st---------0.5p.e.thr 150~160k,1.5p.e.thr 0.5~2k 2nd--------0.5p.e.thr 300~350k,1.5p.e.thr 2~3k→increase the noise rate

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The data sheet of breakdown voltage

6/12MPPC serial number

Bre

akd

ow

n

volt

ag

e

Black:1st-stage

Red:2nd-stage

The variation of breakdown voltage

1st-stage (black) 2nd-stage(red)

The breakdown voltage of 2nd-stage is lower than that of 1st-stage.

Num

ber

of

sam

ple

s

Breakdown voltage (V)

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The variation of pixel capacitance

1st-stage (black) 2nd-stage(red)

The pixel capacitance of 2nd-stage are about same with that of 1st-stage.

Pixel capacitance (pF)

Num

ber

of

sam

ple

s

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MPPC gain vs Over-voltage Gain of 1st-

stage （ black ） and 2nd-stage （ red ） is about the same with Over-voltage.

Over voltage (Vbias- V0)

×105

Gai

n

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Large 　 Chisquare

Noise rate vs Over-voltage

Over voltage (Vbias-V0) Over voltage (Vbias-V0)

Noi

se r

ate

　

(Hz)

The noise rate of 2nd-stage is about 2 times bigger than that of 1st-stage (with Over-voltage).

×103

Noise rate(>0.5p.e.thr)1st-stage

Noise rate(>0.5p.e.thr)2nd-stage

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Crosstalk vs Over-voltage

Over voltage (Vbias-V0)Over voltage (Vbias-V0)

Cro

ss-t

alk

prob

abili

ty

Crosstalk probability1st-stage

Cro

ss-t

alk

prob

abili

ty

The crosstalk of 2nd-stage is about with that of 1st-stage (with Over-voltage).11/12

Crosstalk probability2nd-stage

Summary The measurement of 2nd-stage MPPCs with FPCB has

been finished.

Gain of 2nd-stage （ red ） is about the same with that of 1st-stage （ black ） .

The noise rate of 2nd-stage is 2 times bigger than that of 1st-stage .

The crosstalk of 2nd-stage is about with that of 1st-stage. (with Over-voltage)

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